After writing Ad Hoc Normalization it occurred to me that topic maps offer another form of “ad hoc” normalization.
I don’t know what else you would call merging two topic maps together?
Try that with two relational databases.
So, not only can topic maps maintain “internal” ad hoc normalization but also “external” ad hoc normalization with data sources that were not present at the time of the creation of a topic map.
But there are other forms of normalization.
Recall that Lars Marius talks about the reduction of information items that represent the same subjects. That can only occur when there is a set of information items that obey the same data model and usually the same syntax. I would call that information model normalization. That is whatever is supported by a particular information model can be normalized.
For relational databases that is normalization by design and for topic maps that is ad hoc normalization (although some of it could be planned in advance as well).
But there is another form of normalization. A theoretical construct but subject-based normalization. I say it is theoretical because in order to instantiate a particular case you have to cross over into the land of information model normalization.
I find subject-based normalization quite useful, mostly because as human designers/authors, we are not constrained by the limits of our machines. We can hold contradictory ideas at the same time without requiring a cold or hot reboot. Subject-based normalization allows us to communicate with other users what we have seen in data and how we need to process it for particular needs.